Such a method is known from DE 102 20 348 A1. Whenever a user wishes to use a piece of medical equipment, a check is made as to whether the user is authorized to use said equipment and whether the costs incurred are to be paid before the use thereof. Use is automatically enabled if authorization still exists, and if no costs are outstanding. Alternatively, use is automatically blocked if authorization no longer exists, or if costs are still outstanding.
DE 101 55 092 A1 discloses a method for enabling an operational part of a computer software product and of installations pertaining thereto. As soon as a user wishes to use the operational part of the computer software product, a processor causes a transmitter to transmit a launch signal. It is only when a transponder receives this launch signal and thereupon transmits back an enabling code that the operational part of the computer software product is run.